The present invention relates to conveyors and in particular to diverters for use with conveyors. Specifically, the invention concerns a diverter usable with a line-shaft powered roller conveyor, the diverter being usable to divert objects at a right angle from the main conveyor.
Diverters of many types are well known to the conveyor art. A general characteristic of the one of concern herein is that a transfer mechanism, such as a group of transfer belts, is recessed beneath a transfer surface of the main conveyor when diversion is not desired, the transfer mechanism being raisable above the surface of the main conveyor to engage objects when diversion is intended. Arrangements meeting the above general description are known, and it is the mechanism by which the instant arrangement operates that is unique, in part due to its ability to compensate for problems in prior devices and also for its versatility.
In some conventional diverters, wherein rollers or belts are raised above a conveying surface of a main conveyor, the transfer belts, or the belts used to power rollers if diverter rollers are involved, are stretched during the raising or lowering. This can cause stress to the belts, with increased chance for failure. Further, it can create difficulties in controlling the rate of speed of the diverting rollers.
Many past devices have involved transfer belts or rollers which are mounted in a frame system in such a manner that when they are raised they are also tilted somewhat. That is, an end of the diverter on one side of the conveyor is raised higher than the end at the other side of the main conveyor during diverter operation. This may be inefficient and may cause tilting of objects being diverted which may be undesirable in certain instances. Generally, conventional devices have not satisfactorily solved the problem of having vertical lift with no substantial tilting and without stretching of the transfer belts or drive belts for diverter rollers.
A continual source of problem in conventional systems has been with the provision of adequate power means for the diverter. In some systems a motor or drive mechanism that is independent of the drive mechanism for the main conveyor is used. This requires additional equipment and an increased need for maintenance which increases both the cost and the risk of failure. In some systems it has been found preferable to utilize power derived from the main conveyor itself. In particular, when the main conveyor s a line-shaft powered roller conveyor, the line-shaft is available for powering a diverter if the diverter is of appropriate design.
A problem with using power derived from a main line-shaft in a line-shaft conveyor for a diverter assembly, wherein transfer belts or rollers are raised or lowered with respect to a conveying surface of the main conveyor, has been generated by the fact that while the diverter rollers or belts are raised or lowered, the line-shaft remains stationary. Thus, with conventional systems a drive belt or drive mechanism providing engagement between the diverter and the line-shaft would have to compensate for the relative movement of portions of the diverter with respect to the line-shaft. In the absence of the present invention this would generally require either complex movable idler arm adjustment arrangements or drive belts which stretch. Again, such systems may: require increased maintenance, be expensive, be relatively complicated; be difficult to assemble, and be prone to failure. Further, with such systems it may be difficult to control the rate of speed of the diverter relative to the main conveyor, which is important for ensuring smooth operation.
Generally, conventional diverters are suitable for diversion in one direction only. That is, they are generally assembled for diversion from only one side of a conveyor, i.e., either the right side or the left side. For many such systems switching for operation in an opposite direction is difficult. This is especially true for diverters wherein the diverter not only vertically lifts when objects are engaged but also tilts.
A problem with diverters deriving their power from the main conveyor, such as from a line-shaft in a line-shaft powered conveyer, has been that the line-shaft generally rotates at a fixed, constant rate of speed. Thus, adjustment in the speed of the action of the transfer belts or rollers in the diverter has, in the past, been difficult. In many instances, for many conventional systems, adjustment is not readily possible.
In addition, conventional diverters may have a multitude of moving parts and may need to be manufactured to fine tolerances for operation, both of which will tend to increase the cost of such systems. Generally, it is desirable to produce a diverter system which is not only well adapted for nearly universal application but which is also relatively inexpensive to build and operate by comparison to most conventional systems. Further, it is preferable that such a system be constructed to permit relatively easy access for maintenance and, further, that the design be such as to be relatively free from problems of failure during use.